Analytical model to predict the punching shear strenth of FRP reinforced concrete flat slabs

The use of FRP reinforcement in practice, especially where the corrosion of steel bars is a concern, is very much hampered by the absence of a rational theoretical method of analysis to predict the ultimate strength of structural elements, especially flat slabs and bridge decks, made with FRP-reinforced concrete. This paper aims at evaluating the punching shear capacity of internally, without shear reinforcement, FRP-reinforced slab-column connections. The method is based on a simple analytical model developed by the authors for concrete slabs reinforced with conventional steel. The effects of the FRP elastic modulus, ultimate tensile strength and bond characteristics, which are sufficiently different from those of steel, are incorporated in the existing model. The predictions of the proposed model for FRP-reinforced slabs are then compared with test results obtained from twenty-eight slabs recently reported in the literature. The comparisons show excellent agreement between the predicted and experimental values. It is concluded that the proposed predictive equation presented in this study provides a convenient and reliable framework for the punching strength analysis of slabs reinforced with FRP bars or grids.